Kenya's flower growers are organising armed escorts for this year's rose crop and funding emergency shelters for their pickers to ensure that Valentine's Day is not a flop for British lovers. The industry shuddered to a halt this week as tribal clashes that engulfed Kenya arrived around the shores of Lake Naivasha, where most of the flowers are grown.

Thousands of workers are camped out around Naivasha's police station, too scared to return to the sprawling greenhouses where they earn their living. Millions of roses are now good for nothing other than compost.

Mahmud Abdulla, who runs Lake Flowers, said that he should be packing 45,000 roses a day but was struggling to manage half that. “I don't have the flowers. Next week is the busiest of the year and many of the other farms are going to struggle too,” he said. “Maybe we can recover by Mother's Day but who knows?” His waste bins are full to overflowing with pink, orange and white tinged roses that have been picked too late for export. Half his workforce of 205 is too frightened to return to work.

Naivasha managed to avoid the ethnic clashes that engulfed much of western Kenya in the wake of December's disputed election. That changed on Sunday, when gangs from the Kikuyu tribe of President Kibaki ransacked the town. They sought out members of the Luo tribe - loyal to opposition leader Raila Odinga - and other ethnic groups opposed to the Government. They burnt homes and executed uncircumcised men, marking them out as Luo.

Businesses have also been warned that they will be torched if they do not replace Luos with Kikuyus. Similar scenes have played out across the country as simmering tribal tensions over land, wealth and power came to the surface.

More than 850 people have died in the past month. For now efforts to end the clashes rest with mediation efforts led by Kofi Annan in Nairobi. Yesterday he was joined by Ban Ki Moon, his successor as United Nations Secretary-General. “The killing must stop. The violence must end for the sake of the Kenyan people and for the sake of Kenya,” said Mr Ban after a meeting with Mr Odinga. But with no imminent solution in sight, Mr Abdulla said that he and other managers were trying to send food to their workers.

They are also supporting an aid camp being set up by the Red Cross about five miles around the lake from the town. “It's a precaution so that flower farm workers can stay close to their work,” said Isacko Jirma, of the Kenyan Red Cross Society.

Kenya is the leading exporter of cut flowers to Europe, providing more than a third of all stems sold. “We are arranging for armed police escorts if the roads are blocked again and we might even have to airlift flowers out,” Jane Ngige, the head of the Kenya Flower Council, said.

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